Can you fix a dslr lens that makes noise (sound) when you zoom?

Just to clarify by noise I mean loudness, like a scratching or friction sound. I've been looking at slr cameras for a while, and I definitely want one that shoots video. However the majority of cameras I find make noise when zooming(and i think manually focusing) that gets picked up by the internal mic(kit lens). Can you use something to make it smoother and quieter? WD-40 for example? The cameras I've found with this problem are the Canon t1i and T2i, and the Nikon d3100 and d90 i believe does too. The only one I've found that doesn't so far is the Pentax K-x. These are some examples of what I mean:
http://vimeo.com/...m/15573306 (I know autofocus is making the louder noise)

This has nothing to do with the camera at all, but with the lens. I guess you are using a basic kit lens, which just doesn't work as smoothly as a more expensive one. There's friction between dry parts in there where better quality lenses are greased, thus making the sound.

But the autofocus noise is a pest anyway, so i'd be more worried about that… An external microphone will be the only real solution.

Get an external microphone

http://dancarrphotography.com/blog/2008/11/30/video-accessories-for-the-canon-5d-mark-ii-part-1-microphones/

p.s. WD-40? What do you think will happen if you use it.